It's not every day that a news event involving the stock market has the potential to change the lives of millions of people for the better. But that's what happened today, and although the decision involves some controversy, the latest approval from the U.S. Food and Drug Administration paves the way for a potential breakthrough for the more than 6 million Americans who suffer from a terrible and debilitating illness.

To be clear, the entire stock market didn't celebrate the news. The Dow Jones Industrial Average and S&P 500 were both down on the day, although gains for the Nasdaq Composite were nice to see.


Percentage Change

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S&P 500 (^GSPC 0.03%)



Nasdaq Composite (^IXIC -0.28%)



Data source: Yahoo! Finance.

Indeed, the Nasdaq's gain came in part from the performance of the high-flying stock in question. Biogen (BIIB 0.38%) surged higher by more than 38% on Monday, and the gains came on hopes that the company might finally be able to solve the problem of Alzheimer's disease once and for all.

Medical professional wearing mask holding hand of an older patient.

Image source: Getty Images.

An approval for Biogen

Biogen's stock soared after a long trading halt that lasted nearly three hours. At noon EDT, Biogen issued a press release that announced the FDA's accelerated approval of its aducanumab-avwa treatment for Alzheimer's disease. Using the marketing name Aduhelm for the drug, Biogen claimed the status as having the first and only Alzheimer's treatment addressing what it called "a defining pathology of the disease" by reducing amyloid beta plaque levels in patients' brains.

Biogen said that the FDA issued the accelerated approval based on clinical trial data demonstrating plaque reduction. It'll be up to continuing studies to verify that success in fighting amyloid beta plaque will actually reduce the rate of clinical decline that Alzheimer's disease patients suffer.

CEO Michel Vounatsos calling the approval a "historic moment" and celebrated the decade-long work of numerous researchers. Officials at Eisai (ESALY -0.05%), which has worked together with Biogen on the treatment, were similarly pleased. Eisai stock jumped as much as 70% in over-the-counter trading.

Why Biogen's win is controversial

Yet others remain skeptical about Biogen's victory. Although the company has done a good job of showing the direct impact of the treatment on amyloid protein formation, making the further link to demonstrate actual improvement in Alzheimer's symptoms like cognitive ability has been more elusive. In fact, past trials have specifically failed to establish statistically significant benefits.

Also unusual is the extent of disagreement among researchers in the field. A panel of independent experts wasn't convinced when presented with Aduhelm's results that the treatment could directly improve symptoms.

Nevertheless, Biogen can expect sales of Aduhelm to be brisk. With the only approved treatment on the market, Biogen will have many medical professionals looking to try it even if they're skeptical about its eventual impact. That will inevitably produce billions of dollars in revenue for Biogen while allowing the company to continue collecting data on any positive impacts of the treatment on patients.

Hoping for a cure

It's precisely because so much is on the line for so many people that Biogen's Alzheimer's treatment generates such strong emotion. Nevertheless, everyone has to be hoping that Aduhelm will be able to prove itself once and for all and start providing relief for those who suffer from the disease.